Baja Music Man guitar and bass onboard preamps

Jarno · Post by **Jarno** » 02 Apr 2010, 19:54

What kind of pickups are they?

collingtech · Post by **collingtech** » 02 Apr 2010, 22:05

emg , the same used by les claypool from primus, i dont remeber the exact model , will look

edit : model 40dc

edit 2: as a already state this preamp sound wonderfull whit non active pickups :0)

PaulBass · Post by **PaulBass** » 12 Apr 2010, 07:14

I got a tip from somebody who's been building bass preamps for 40 years. I used a .047uf Nichicon metal film polyester cap and he said to swap it for a Wima MKP-2. Wow did that make difference! Now it sounds even better! He also said to use Nichicon electrolytics and Dale resistors, which I already had

Jarno · Post by **Jarno** » 12 Apr 2010, 11:26

Ah, you have an audiophile friend. Surprised he didn't propose Black Gate electrolytics. For even more high-endedness, try bypassing the output cap with a small filmcap 10-100nF or so.

PaulBass · Post by **PaulBass** » 12 Apr 2010, 18:55

Jarno wrote:Ah, you have an audiophile friend. Surprised he didn't propose Black Gate electrolytics. For even more high-endedness, try bypassing the output cap with a small filmcap 10-100nF or so.

thanks for the tips! I heard about those Black Gates but I read they have a long burn-in period and I didn't have the patience for it. He said the japan made Nichicons give the most bang for the buck. I was surprised at the impact the little red $.40 Wima cap had on the sound, it took the tone to another level. Which cap is the output? I can swap that and see what it sounds like

Jarno · Post by **Jarno** » 13 Apr 2010, 07:42

Here you can find two articles about the different types and characteristics of capacitors. Basically, if fidelity or ideal behaviour is what you're looking for (not always in a stompbox), you can spend a ton of money on one expensive cap but you can also combine a number of inexpensive caps to make one cap with very good characteristics.
I've heard good things about the Black Gates, but I wonder if you can't combine a electrolytic with a filmcap and reach the same level.

PaulBass · Post by **PaulBass** » 06 Jun 2010, 20:50

I noticed that Ernie Ball discontinued the licenses. All the Music Man copy basses are being bootlegged overseas. I guess EB wants everybody to buy the $2,000 reissues. Bass players are buying the MM copies and making this preamp for it, it's really jumping at talkbass.com. I made 3 of these preamps for 3 copy basses so far. It may not be exactly EB quality but the sound is there. I saved a ton of $$$

bajaman · Post by **bajaman** » 06 Jun 2010, 21:43

Hi PaulBass
that is great news to read

cheers
bajaman

seele · Post by **seele** » 08 Jul 2010, 21:45

Hey Baja,

thanks for the schematic! I used the preamp for an old Stingray i restored some days ago and it sounds really good.
I did a perfboard layout for this, i hope it's okay for you.

bajaman · Post by **bajaman** » 09 Jul 2010, 00:16

Hey seele
That's great

cheers
Bajaman

HENK · Post by **HENK** » 09 Jul 2010, 08:46

Duckman · Post by **Duckman** » 09 Jul 2010, 14:24

Treble pot lug 2... to ground?

deltafred · Post by **deltafred** » 11 Jul 2010, 10:55

Duckman wrote:Treble pot lug 2... to ground?

The wiper, pin 2, of the Treble pot should go to LM4250 pin 2, not pin 4.

It would also be nice to see which way round the LM4250 goes. I know pin 1 on the perfboard Is marked but there is no indication on the IC outline (unless the white wire is masking it). I know which way round it goes but I've been an EE for 40 years. It may just save a bit of confusion and a few fried LM4250s.

Great work everyone, especially Bajaman for reverse engineering and posting the schematic.

I copied my MM Stingray 2 band pre a while ago and built a clone and then found this thread.

There are slight differences in component values between Bajaman's original pre EB schematic and the current EB one that I used but they are so slight as to be almost negligible.

I had a cheap 3 band pre Chinese Stingray copy that sounded dreadful. The pickup was muddy and the 3 band pre gave 3 bands of mud. Even when I cross wired them to my Stingray, both pre and pickup were still muddy.

I fitted the clone 2 band pre, changed the magnets in the pickup to Neo, added a 4 way rotary switch in the spare pot hole for Coil1, Coil2, Parallel, Series, and wow what a sound! If this were the only bass I owned I would happily play it to every gig. This was supposed to be my hack bass but it sounds so good I don't want to change it now. What I need is another Chinese Stingray copy.

fred

PaulBass · Post by **PaulBass** » 11 Jul 2010, 22:15

seele wrote:Hey Baja,

thanks for the schematic! I used the preamp for an old Stingray i restored some days ago and it sounds really good.
I did a perfboard layout for this, i hope it's okay for you.

the treble wiper is suppose to go between the 220K resistor and pin 2 on the IC. the perf layout is incorrect

wrnchbndr · Post by **wrnchbndr** » 16 Jul 2010, 21:47

Baja, Much thanks for an excellent post that has gone on so long that it now has all sorts of really cool additional stuff. I have the parts on hand and am just waiting for delivery of my press and peel. I've never tried my hand at PC board etching so this is certainly going to be an adventure.

This is my first post into this forum. My name is Mark and I use the handle of Wrench Bender on a number of forums. I am a professional luthier and the service manager at a small privately owned music store in NJ. I often have need for preamps and am seriously frustrated that there aren't inexpensive preamps available from my major suppliers while the price for all of the parts to build three of the stingray preamps is under $25.

Does anyone have any recommendations for a similar post describing the build of a piezo preamp with a two or three band EQ that would be decent for an acoustic instrument?

I'll get back to this post when I've completed my first stingray preamp.

In the mean time some folks might appreciate this:

http://www.guitarjonesusa.com/catalog/s ... how_detail

I purchased a number of these some time ago when the price was a bit lower for a series of basses that I was building. These are anything but impressive when used passively but they may liven up with the preamp. I'm serious, they stink in a passive application but they look cool and they're cheap.

bajaman · Post by **bajaman** » 16 Jul 2010, 22:21

Always happy to help out - thanks for the link too

- welcome to the fsb forum

cheers
bajaman

seele · Post by **seele** » 19 Jul 2010, 21:18

Yeah sorry... the wiper of the treble pot should be connected to the free solder pad next to it.

just wondering how someone would try to squeeze a lead throught the ic socket.

bajaman · Post by **bajaman** » 19 Jul 2010, 21:42

the lead went over the IC in the original

bajaman

wrnchbndr · Post by **wrnchbndr** » 31 Jul 2010, 14:35

Okay I got my press and peel and it works a lot better than I thought it would. Remember this is my first PCB. The problem is that I did not consider the implications of drilling holes though tiny little runs so I made my PCB a bit too delicate. I'm redrawing the PCB with bigger pads and runs to make it more tolerent of using a demel to make the holes. The IC holes will be the critical challenge and if I make more of these I'll go with a surface mount instead of hole-through.

I'm using a home-made etchant recipe that I found on the web that is a mixture of muratic acid and hydrogen peroxide it worked great.

wrnchbndr · Post by **wrnchbndr** » 06 Aug 2010, 12:20

Total SUCCESS! I built the PCB exactly as descibed and it worked the very first time and sounds fantastic. Even with those faux-bogus Musicman pickups. The use of this preamp broadens up the total harmonic response and I can get exactly what I want via the tone controls. There is punch and a quality to the tone that just didn't exist before. There is no noise at all. I was thinking that I ought to shield the wires but this is completely unnecessary. I'm happy as hell and will use this preamp in every bass that I build. My next step is to employ SMDs for the same circuit and shrink it down. I have no experience with this but this was the first time I built a PCB and I'm feeling perky.

I'm suspicious of info like this on the internet and gave the outcome of this project a 50/50 chance. The info on this preamp in this post is 100% dependable and the result is a project that is very worthwhile.

Additionally, I'm thinking of adding this circuit to one of my home built 5E3 amps. The amp is overly "preamppy" -- it breaks up too soon with preamp distortion. I'll just insert this right on the other side of the input jack and lable the volume as preamp gain. I'll delete the existing tone control and use the bass and treble of the preamp instead.

Today, I'm installing this preamp into a LP Jr that I built. It has a single Gibson P90 and I'll evaluate the frequency response to see if I really need to modify the circuit at all for use in a guitar. At the moment, I have the preamp wired with jacks on each end so I can simply plug anything into it I want -- like an efffects pedal which isn't a bad idea in itself either.

Baja Music Man guitar and bass onboard preamps [documentation]